The proposed research is an extension of our Diabetes Epidemiology Research International Mortality Study. We have been determining the mortality status for over 8,000 youth onset cases diagnosed between 1965-1979 from four population-based cohorts in Japan, Israel, Allegheny County, PA (U.S.A.) and Finland. Major between country differences in mortality are emerging for both total and cause-specific rates. Through 1/1/85, 147 deaths have been identified. We propose to follow these cohorts to 1/1/94, during which time an additional 450 deaths are predicted to occur. This will permit the evaluation of long-term cause-specific differences by country (Aim I). An additional 4,000 incident cases diagnosed from 1/1/80 to 12/31/89 will be included in order to assess secular trends in IDDM mortality (Aim II). Finally, population based cohorts from Canada, Norway, Poland and the Soviet Union will be available for additional cross-country comparisons (Aim III) which include over 3,700 cases. This will expand the evaluation of mortality to seven quite different countries consisting of over 16,000 cases and 600 expected deaths. By accomplishing these specific aims, we hope to begin to determine the reasons for the major differences in mortality between IDDM cases in the U.S. and other countries.